Modern day aqueous cement containing compositions are complex mixtures of materials. The cement containing compositions can contain materials which increase or retard the setting rate, reduce the viscosity or slump of the cement containing mixture, increase air entrainment, reduce air entrainment and have other functions.
The present invention relates to an aqueous cement composition. More particularly, the invention concerns the incorporation into a cement composition of a glycoside surfactant composition as a dispersant, setting retarder, air entraining agent or a combination of such properties.
Dispersing agents are valuable in cement slurries in that they reduce the apparent viscosity of the slurry to permit easier handling of the cement slurry. However, the dispersing agents can also be useful in reducing the ratio of water to cement so that a stronger cement containing composition can be obtained.
As is well understood in the art, upon addition of water to Portland cement, an exotherm appears shortly thereafter due to the dissolution and wetting of the cement particles. The initial exotherm subsides and after an induction period, hydration or an accelerated setting phase begins. The two exotherms are clearly shown in FIG. 5 where the first exotherm occurs in about 10 minutes and the second hydration or accelerated setting exotherm occurs at about 490 minutes.
It is also necessary at times to retard the setting of cement. The present invention provides a composition which can retard the setting of cement for extended periods of time. In addition, a small amount of the additive of the present invention can substantially increase the air entrained in a cement containing composition. If the reduction in slump or the length of time the setting of cement must be retarded requires a substantial amount of the additive of the present invention, it may be necessary to introduce into the composition a foam inhibitor to reduce the amount of air entrained in the cement.